Quelle  apple-efuses.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Apple SoC eFuse driver
 *
 * Copyright (C) The Asahi Linux Contributors
 */

#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/platform_device.h>

struct apple_efuses_priv {
 void __iomem *fuses;
};

static int apple_efuses_read(void *context, unsigned int offset, void *val,
        size_t bytes)
{
 struct apple_efuses_priv *priv = context;
 u32 *dst = val;

 while (bytes >= sizeof(u32)) {
  *dst++ = readl_relaxed(priv->fuses + offset);
  bytes -= sizeof(u32);
  offset += sizeof(u32);
 }

 return 0;
}

static int apple_efuses_probe(struct platform_device *pdev)
{
 struct apple_efuses_priv *priv;
 struct resource *res;
 struct nvmem_config config = {
  .dev = &pdev->dev,
  .add_legacy_fixed_of_cells = true,
  .read_only = true,
  .reg_read = apple_efuses_read,
  .stride = sizeof(u32),
  .word_size = sizeof(u32),
  .name = "apple_efuses_nvmem",
  .id = NVMEM_DEVID_AUTO,
  .root_only = true,
 };

 priv = devm_kzalloc(config.dev, sizeof(*priv), GFP_KERNEL);
 if (!priv)
  return -ENOMEM;

 priv->fuses = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 if (IS_ERR(priv->fuses))
  return PTR_ERR(priv->fuses);

 config.priv = priv;
 config.size = resource_size(res);

 return PTR_ERR_OR_ZERO(devm_nvmem_register(config.dev, &config));
}

static const struct of_device_id apple_efuses_of_match[] = {
 { .compatible = "apple,efuses", },
 {}
};

MODULE_DEVICE_TABLE(of, apple_efuses_of_match);

static struct platform_driver apple_efuses_driver = {
 .driver = {
  .name = "apple_efuses",
  .of_match_table = apple_efuses_of_match,
 },
 .probe = apple_efuses_probe,
};

module_platform_driver(apple_efuses_driver);

MODULE_AUTHOR("Sven Peter ");
MODULE_DESCRIPTION("Apple SoC eFuse driver");
MODULE_LICENSE("GPL");